Water Tables in Paired Artificially Drained and Undrained Soil Catenas in Iowa

This study was initiated to study water table fluctuations and the influence of artificial drainage on soil morphology. Water table depth and duration for one artificially drained and one undrained soil sequence on paired landscapes were measured. Landscapes were composed of six soil series: Clarion (Typic Hapludolls); Nicollet (Aquic Hapludolls); Webster (Typic Haplaquolls); Canisteo (Typic Haplaquolls); Harps (Typic Calciaquolls); and Okoboji (Cumulic Haplaquolls). Morphological properties of paired soil series were compared and related to water table fluctuations. Soil morphology and water table depth and duration were highly correlated for the Aquolls in the undrained traverse but not in the artificially drained traverse. Webster, Canisteo, Harps, and Okoboji in both traverses have endosaturation, contain redoximorphic features, and meet the criteria of hydric soils. In the undrained traverse, Okoboji meets the additional requirements of vegetation and hydrology, and qualifies as a wetland, while Webster, Canisteo, and Harps classify as farmed wetlands. Webster, Canisteo, Harps, and Okoboji in the artificially drained traverse met the criteria of prior converted cropland. A drained phase should be recognized for Webster, Canisteo, Harps, and Okoboji. We suggest that all soils with water table depths modified by artificial drainage have a separate soil interpretation record and be recognized as a drained phase. This proposed change would help reduce confusion in the use of data recorded on the soil interpretation record.